More colon cancer cases diagnosed in younger adults, with advanced disease more likely

Sept. 2, 2020

Although most cases of colon cancer are still diagnosed in older people, studies have confirmed that there has been an increase in cases in adults younger than 50 — while cases in adults over 50 have been on the decline, mostly as a result of a big push to get this older group screened for colorectal cancer, which includes tumors in the rectum or the colon, wrote John Fernandez in a Baptist Health South Florida news report. 

Colorectal cancer is the second-leading cause of cancer deaths in the U.S. for men and women combined. Colorectal cancer is an umbrella term often used to describe several different types of cancers found in the large intestine. A recent report by the American Cancer Society found that cases have been rising by about two percent annually in people under 50.  

A study last year found that diagnoses of colorectal cancer in adults under the age of 50 are more likely to be of advanced disease. The study also found that the proportion of young adults being diagnosed was higher in African-American and Hispanic populations, compared to non-Hispanic whites, from 2004 to 2015.  

The trend toward younger adults is striking and still somewhat of a mystery to researchers. Lifestyle factors, including a persistent obesity epidemic in the U.S., is considered a contributor to the rise in colorectal cancer among younger people.  

Two years ago, the American Cancer Society (ACS) modified its screening guidelines. People at average risk should start getting screened for colorectal cancer at age 45, instead of 50, the guidelines recommend. ACS’ guidance applies to adults at average risk for colorectal cancer who do not have symptoms. It does not apply to adults with a family history of colorectal cancer, a history of inflammatory bowel disease, genetic syndromes such as familial cancerous polyps, a personal history of previous colorectal cancer or benign polyps, or other risk factors.  

“Early screening is indicated if there is a first-degree relative with history of colorectal cancer and in patients with known high-risk genetic syndromes such as hereditary nonpolyposis colorectal cancer,” says Michael Chuong, M.D., a radiation oncologist at Miami Cancer Institute who specializes in the treatment of gastrointestinal cancers. “Early screening should begin at 40 years or 10 years before the first-degree relative’s diagnosis, whichever is earlier.”  

In last year’s study, researchers with the departments of internal medicine and oncology at the University of Texas at Austin, focused on trends over the past two decades. Looking at data from the National Cancer Database registry, they found that 12.2 percent of colorectal cancer diagnoses in the U.S. in 2015 were in people under the age of 50 years, compared with 10 percent in 2004. A total of 1.1 million cases were included in the study.  

More strikingly, researchers found signs of advanced disease in more than half (51.6 percent) of colorectal cancer diagnoses in younger adults — compared with 40 percent in those over 50 years of age. The team reported their findings in a Cancer journal paper.  

Baptist Health South Florida has the report